forget it, I've seen the manual, it's the same encoder
Indeed. I only handle the playback side 
It required me to compose a song like Awesome (including spelling errors 
) to truly convince myself of the added value these samples can have. I have been postponing the 'full' implementation for a long time, because one: the earlier hack was a rather unstable one because samples are 'streamed' from v9990 vram and had to implement a lot shielding throughout the general code to get it stable (never planned for this from the start) and two: memory issues, I had to do various code size optimizations to get it to fit. For example I kicked it out before to make room for the FM syntheses stuff... Anyway it is now all in there and hopefully stable and worth it for all the rework after all.
Getting good samples will remain to be the most challenge part. It could helpful to have some kind of sample editing tool, where one could make e.g. small corrections, boost volume, add and edit looping positions, improve looping by some cross fading etc.
I understand the learning curve for Realfun 3 is a rather steep one, but I still hope for the day someone (other than me) would compose a nice Realfun 3 song!
Maybe this new feature and demo song could convince anyone to give it another try.
Past few days I have been working on a ISR sample editor. It gives a nice visualization of the samples and more.
Below you can find a a demonstration video using the ISR sample editor to add a loop to samples and modifying a few bins to improve the sound a bit. I might be a bit boring to watch, but I thought, let's just post it anyway for curious ones
Realfun 3 ISR sample editor